Blink GC plugin: require that trace call base::trace and traceAfterDispatch...

Blink GC plugin: require that trace call base::trace and traceAfterDispatch call base::traceAfterDispatch.

BUG=334149
R=wibling@chromium.org
NOTRY=true

Review URL: https://codereview.chromium.org/278523004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@270057 0039d316-1c4b-4281-b951-d872f2087c98

tools/clang/blink_gc_plugin/BlinkGCPlugin.cpp

@@ -356,10 +356,13 @@ class CheckTraceVisitor : public RecursiveASTVisitor<CheckTraceVisitor> {
         return true;
       }
 
-      // TODO: It is possible to have multiple bases, where one must be traced
-      // using a traceAfterDispatch. In such a case we should also check that
-      // the mixin does not add a vtable.
-      if (Config::IsTraceMethod(fn) && member->hasQualifier()) {
+      // Currently, a manually dispatched class cannot have mixin bases (having
+      // one would add a vtable which we explicitly check against). This means
+      // that we can only make calls to a trace method of the same name. Revisit
+      // this if our mixin/vtable assumption changes.
+      if (Config::IsTraceMethod(fn) &&
+          fn->getName() == trace_->getName() &&
+          member->hasQualifier()) {
         if (const Type* type = member->getQualifier()->getAsType()) {
           if (CXXRecordDecl* decl = type->getAsCXXRecordDecl()) {
             RecordInfo::Bases::iterator it = info_->GetBases().find(decl);

tools/clang/blink_gc_plugin/tests/finalize_after_dispatch.cpp

@@ -45,19 +45,19 @@ void A::finalizeGarbageCollectedObject()
 void B::traceAfterDispatch(Visitor* visitor)
 {
     visitor->trace(m_a);
-    A::trace(visitor);
+    A::traceAfterDispatch(visitor);
 }
 
 void C::traceAfterDispatch(Visitor* visitor)
 {
     visitor->trace(m_a);
-    A::trace(visitor);
+    A::traceAfterDispatch(visitor);
 }
 
 void D::traceAfterDispatch(Visitor* visitor)
 {
     visitor->trace(m_a);
-    Abstract::trace(visitor);
+    Abstract::traceAfterDispatch(visitor);
 }
 
 }

tools/clang/blink_gc_plugin/tests/trace_after_dispatch.cpp

@@ -30,19 +30,21 @@ void A::traceAfterDispatch(Visitor* visitor)
 void B::traceAfterDispatch(Visitor* visitor)
 {
     visitor->trace(m_a);
-    // Missing A::trace(visitor);
+    // Missing A::traceAfterDispatch(visitor);
+    // Also check that calling trace does not count.
+    A::trace(visitor);
 }
 
 void C::traceAfterDispatch(Visitor* visitor)
 {
     // Missing visitor->trace(m_a);
-    A::trace(visitor);
+    A::traceAfterDispatch(visitor);
 }
 
 void D::traceAfterDispatch(Visitor* visitor)
 {
     visitor->trace(m_a);
-    Abstract::trace(visitor);
+    Abstract::traceAfterDispatch(visitor);
 }
 
 }

tools/clang/blink_gc_plugin/tests/trace_after_dispatch.txt

@@ -4,7 +4,7 @@ void A::trace(Visitor* visitor)
 trace_after_dispatch.cpp:30:1: warning: [blink-gc] Base class 'A' of derived class 'B' requires tracing.
 void B::traceAfterDispatch(Visitor* visitor)
 ^
-trace_after_dispatch.cpp:36:1: warning: [blink-gc] Class 'C' has untraced fields that require tracing.
+trace_after_dispatch.cpp:38:1: warning: [blink-gc] Class 'C' has untraced fields that require tracing.
 void C::traceAfterDispatch(Visitor* visitor)
 ^
 ./trace_after_dispatch.h:36:5: note: [blink-gc] Untraced field 'm_a' declared here:

tools/clang/blink_gc_plugin/tests/virtual_and_trace_after_dispatch.cpp

@@ -24,7 +24,7 @@ void A::traceAfterDispatch(Visitor* visitor)
 void B::traceAfterDispatch(Visitor* visitor)
 {
     visitor->trace(m_a);
-    A::trace(visitor);
+    A::traceAfterDispatch(visitor);
 }
 
 }